by Ian Kuah
Five seconds is an eternity at the Nurburgring Nordscheife, where a new lap record can be a kingmaker. In October last year, the Lamborghini Huracn Performante blitzed the Porsche 918 Spyder's three-year old production sports car lap record by five seconds, when it clocked the amazing 6:52.01 minute lap. Six months later, on September 27, Porsche returned the favor when the new GT2 RS set a blazing 6:47.30 min lap time, toppling the Lamborghini's record by an equal amount.
3.8-liter Twin-Turbo Flat 6 Gas
But just as impressive as its sheer pace is the fact that Porsche's new Ring champion is rear-wheel-drive, whereas the 918 Spyder and Huracan Performante both rely on all-wheel-drive for optimum traction. When I first saw the bignumbers of 700 hp and 553 lb ft of torque not to mention the cars intimidatingappearance I naturally assumed it was going to be an animal from behind the wheel.The reality could not be further from the truth, and as I drove at town speedsfrom the hotel to the Portimao Circuit, I quickly found that apart from anoticeably stiffer ride than the GT3 or GT3 RS, the GT2 RS actually has adocile side that makes it as tractable as a normal 911 Turbo.
The massive torque at modest engine speeds means you can trickle around a gear higher than you think. If anything you don't want to use too low a gear to avoid lighting up the back end on cold tires. With a roll cage and six-point harnesses in addition to the normal inertia reel seat belts, the lightweight interior is a bit of a contradiction since it is finished in the finest leather and Alcantara with exquisite detailing. You do notice the relative lack of soundproofing as road noise comes through loud and clear, but hey, it is a street legal trackday weapon after all. I ran in PDK Sport most of the time, and tried the stiffer damper setting momentarily. This was not comfortable on the road and I quickly went back to the stock damper setting.
The Porsche 911 GT2 genre has a rather potted history. The original 993 GT2 of 1996 was arguably the wildest looking of the bunch. With its huge bolt-on wheel arches and big rear wing with intercooler intake ducts, this twin-turbo 3.6-liter machine with 450 hp and 432 lb ft of torque looked like the race homologation special it was. The factory-backed race version in its original and Evo form took many class wins in the GT2 category of the BPR Global GT Series. Although it soon gave best to the Dodge Viper, the GT2 exited on a high note in 1999, the final season of its official race career, with a class win in the 24 Hours of Daytona 1999.
With the writing clearly on the wall, Porsche moved on to its bespoke mid-engine racecar named after the GT1 category it contested. The 996 GT2 that debuted in 1999 was never meant to race, and was instead a cynical marketing exercise for wealthy owners to bask in the glory of its illustrious predecessor. With tricky handling from day one, the 996 GT2 became a prime candidate for aftermarket tuners to swap out the factory suspension and further boost its 462 hp output, later increased to 476 hp. By this time Porsche was well settled in the naturally-aspirated GT3 category, and the 997 GT2 came along in 2007 bearing 530 hp and 505 lb ft of torque with no designs on racing.
With a 0-62 mph time of 3.9 seconds and a top speed of 204 mph, this was a genuine supercar whose 7:32.0 min Nurburgring lap time in the hands of Walter Rohrl equaled the time he had set in the mighty 612-hp Carrera GT just three years previously. Of course Andreas Preuninger, Director of GT cars, and his team never sits still, and for the RS version that debuted in 2010, they trimmed 154 lb from the GT2, uprated its chassis and increased engine output to 620 hp. Walter Rohrl turned in a sub-7:18 min lap time with this car. Put in another way, that is 14.0 seconds faster than the Carrera GT.
Ironically despite lacking all these exotic materials like carbon-fiber and magnesium, the largely steel and aluminum 997 GT2 RS was actually 22 lb lighter than Porsche's flagship supercar. Fast-forward to 2017 and in a massive break with tradition, Porsche have jumped straight to the 991.2 GT2 RS this time round, with no GT2 model in sight since the current 991 was launched in 2011. The reason for this according to Andreas Preuninger is quite simple. "The current Turbo S is so fast and competent that had we made a 620 hp or 640 hp GT2 it would have been rather lukewarm. So we decided to wait a while and develop a special car that would genuinely raise the bar."
Aesthetically, the new GT2 RS is as wild and aggressive looking in its own way as the car that kicked off the Porsche GT2 family 21 years ago. While your eyes home in on the front fender vents that come straight from the GT3 RS, and the tall motorsport sized rear wing, you are soon drawn back to the massive air intakes in the front bumper and its prominent lip spoiler. These big intakes are not just for show as a twin-turbocharged motor making 700 hp burns a lot of fuel that in turn makes an awful lot of heat that has to go somewhere. These radiators are the same units used by the GT3 RS and Turbo S; one big water radiator on each side of the front and one in the center.
Only the outer radiators have thermostatically controlled electric fans, which have been uprated to 600 watt each. The only other physical change here is the much bigger air intakes on the front bumper to get more ram air to the radiators. The bespoke water-cooled intercoolers are both larger and thicker than the Turbo S units, and have around 10 percent more efficiency. The ram air from the intakes behind the doors is channeled via larger pipes over the big rear wheels. Charge air temperature is an issue with this level of power and the cooler the intake air, the more power can be produced and the lower the thermal load on the engine.
To this end, the engineers came up with a water spray system for the intercoolers, which mists them when the intake temperature reaches 50 degrees C. This computer-controlled system also looks at the temperature gradient and directs the appropriate amount of water from the 5.0 liter reservoir. The result is a very significant reduction in intake temperature by up to 20 degrees C. This allows peak performance to be sustained on track even in high ambient temperatures. The two bespoke turbochargers feature larger turbine and compressor wheels required for this engine's significantly greater output. Both the engine and the 7-speed PDK gearbox have uprated oil coolers to help them withstandsustained track driving.
The big numbers are 700 hp at 7,000 rpm and 553 lb ft of torque from 2,500 to 4,500 rpm. That rockets the 1,470-kg GT2 RS to 60 mph in 2.7 seconds, to 100 mph in 5.8 secs, to 124 mph in 8.3 secs and on to a 211.3 mph top speed. Delivering this much power and torque to the tarmac requires a rather special chassis. The man behind the set up is Holger Bartels, whose work on the 918 Spyder, GT3 RS and 991.2 GT3 can only be described as outstanding. Uwe Braun, Manager, Complete Vehicle Motorsport GT Model Line, explained that Porsche never uses just one source for tires. "The GT2 RS uses the latest Michelin Cup 2 tires alongside the equivalent Dunlop Sport MAXX.
The Michelin has a tread depth of 5.0 mm when new and is a touch better in the dry, while the Dunlop, with a 6.5 mm tread depth, has the edge in the wet. Of course neither can cope with standing water, but their grip in normal wet conditions is very impressive compared to earlier generations of track ready road tires. While they are the same size as on the GT3 RS and the 918 Spyder, these tires were specially developed for the GT2 RS whose different load and power characteristics make this a necessity," Uwe continued. "The gap in the specification and performance between the GT3 RS and GT2 RS tires is similar to that between the first and second generations of 991 GT3."
The tires were developed in combination with the suspension, which is fundamentally similar to the GT3 RS, but has been further developed to work optimally with the different aerodynamics and power. "A lot of work was done on the rear suspension which has to bear the brunt of the more powerful engine," said Uwe. "With so much power on tap, traction was a priority along with decent ride comfort for road use. We only use Uniball suspension bushes here along with completely different spring and damper rates. While the GT3 RS has spring rates of 45 Nm/mm in front and 120 Nm/mm at the rear, the GT2 RS springs are rated at 100 and 160 Nm/mm respectively, which is similar to the Cup car," he explained.
"With such stiff springs supporting the car we then had a lot of work to do on the damping to produce an acceptable ride quality." A lot of work was done to reduce sprung and unsprung weight and this includes bespoke carbon-fiber uprights for each rear hub, and a carbon-fiber rear anti-roll bar. The huge PCCB ceramic brakes are the same as the GT3 RS, which in turn are shared with the heavier 918 Spyder, so they are more than up to the job of stopping the GT2 RS. That said, these big brakes benefit from extra cooling via ram air ducting that runs through bespoke openings in the body-in-white unique to the GT2 RS. It is obvious form its racecar looks that aerodynamics play a huge part in the stability of the GT2 RS.
"We have a total of 300 kg of downforce at 340 km/h with the rear wing in its normal position of two degrees positive," explained Andreas Preuninger. "The wing is adjustable and produces 400 kg of downforce when it is in its track position with four degrees angle of attack." Downforce is always a trade-off against drag, and the GT2 RS has a Cd of 0.35. On track, the sport damper setting really came into its own. Portimao has a smooth and grippy surface but this very fast circuit has significant elevation changes in places and a very long straight. I know Portimao pretty well and so was able to concentrate on what the GT2 RS was telling me as I circulated faster and faster.
The GT team have done an amazing job and the car feels totally progressive, predictable and safe in the hands of an experienced driver. Front-end bite is impressive, but the best way to tackle bends is the time honored: slow in, fast out. Get your speed down, trail brake in to settle the nose, and don't be too greedy with the throttle and the RS holds the chosen line with astounding mechanical grip. The fastest exit is gained by gently applying throttle as you open the steering past the apex, and then the cars pace from a bend is amazing. You always have to remember how much grunt you have at the touch of your right foot, and the fine balance between exiting a bend as fast as you can go and the back end moving into power oversteer is a fine one.
That said, the engineers have managed to give this potent twin-turbo motor such a finely adjustable throttle that metering the horses feels really natural and easy. When it does let go, the back end is easy to catch, and so long as you don't give it too much gas you can hold it in a drift with no sense of snappiness. As good as the chassis is, you always have to remember how much power has to go through those rear tires, and here the mountain of torque means you can drive a gear higher than you would in a naturally-aspirated car. This way you maintain momentum and do not get into a low gear, high revs situation that will over-drive the chassis in a bend. The GT2 RS is the fastest street legal car I have driven at Portimao.
I know this track to the point where I can tell you more or less what speeds you reach before braking at the end of each straight. Never before have I exited the bend leading to the main straight at close to 120 mph, with a 180 mph terminal velocity at the end. The counterpoint is how docile the car is at legal road speeds. Porsche's new GT2 RS is a stunning achievement for Andreas Preuninger's team. Not only has it obliterated the record setting lap times of its hypercar sister and its 4WD Italian cousin, it has also set an all time benchmark for traditional rear-wheel-drive sports cars.